Senior FullStack Developer (.NET/Javascript/React)

CI&T; Brasil; On-site; BRL 150,000 - 250,000; Full time

Benefits offered by this job

Health and dental insurance

Meal and food allowance

Extended paternity leave

Wellness partnerships (Gympass/Total)

Profit Sharing and Results Particip.

Life insurance

CI&T University

Discount club

Well-being platform access

Parenting course

Online learning partnerships

Language learning platform

Job summary

CI&T is seeking a skilled software engineer to design, build, and maintain scalable full-stack applications using .NET Core and React. You will address security, optimize performance, and implement robust testing with CI/CD in a collaborative,Mentor-driven environment.

The role emphasizes using AI tooling to accelerate delivery, conduct thorough code reviews, and guide junior teammates while maintaining high standards for quality and security across frontend and backend systems.

Qualifications

• Experience designing and delivering full-stack apps with .NET Core and React.
• Ability to address security vulnerabilities following OWASP guidelines.
• Proven track record of improving performance and reliability.
• Experience leading code reviews and mentoring teammates.

Responsibilities

• Design, build, test, and maintain scalable, secure full-stack apps using .NET Core and React.
• Address security vulnerabilities across frontend and backend codebases per OWASP.
• Translate architecture guidelines into clean, maintainable code and contribute to design discussions.
• Monitor, troubleshoot, and optimize application performance and interactions.
• Leverage AI tools (e.g., Claude Code) to accelerate feature delivery and testing.
• Drive test coverage and enforce CI/CD standards within the pipeline.
• Conduct peer code reviews, mentor junior/mid-level developers, and foster learning culture.

Skills

Proactive Ownership

Critical Thinking

Adaptability

Problem Solving

Communication

Team Collaboration

AI Enthusiasm

Tools

NET Core

React

Job description

At CI&T, we help large enterprises transform the potential of AI into real business impact with AI Deployment, AI-native execution, and tech-integrated business solutions.

With 30 years of experience in technological transformation, we accelerate innovation with expertise in Agentic SDLC, Application modernization, Data & AI, Martech and Business strategy.

We are 8,000 CI&Ters across more than 25 countries, collaborating to build solutions with real impact. AI is already part of how we work, evolve, and innovate every day.

Job Overview

Key Responsibilities:

• Feature Engineering & Delivery: Design, build, test, and maintain scalable, secure, and resilient fullstack applications using .NET Core and React.
• Security & Best Practices: Actively address security vulnerabilities across both frontend and backend codebases, adhering to modern secure coding standards and OWASP principles.
• Architecture Implementation: Translate architectural guidelines into clean, maintainable, and well-tested code, contributing actionable technical insights to team design discussions.
• Performance Optimization: Continuously monitor, troubleshoot, and optimize application performance, reliability, and backend/frontend interactions.
• AI Tooling & Developer Velocity: Utilize AI tools and agentic workflows (e.g., Claude Code) to accelerate feature delivery, cross-file refactoring, and automated testing.
• Quality & Testing Ownership: Drive test coverage (unit, integration, end-to-end) and enforce robust code quality and CI/CD standards within the development pipeline.
• Team Leadership & Mentorship: Conduct thorough peer code reviews, mentor junior and mid-level developers, and foster a collaborative, continuous-learning culture.

Soft Skills

• Proactive Ownership: Demonstrates initiative by identifying challenges early, proposing pragmatic solutions, and taking end-to-end responsibility with minimal supervision.
• Critical Thinking: Questions underlying assumptions and analyzes problems from foundational concepts up, ensuring deep technical comprehension before taking action.
• Adaptability & Continuous Learning: Eagerness to learn new languages, frameworks, and engineering tools as technical demands evolve.
• Problem Solving: Strong analytical skills with a track record of diagnosing and resolving complex technical issues in production environments.
• Communication & Collaboration: Excellent written and verbal communication skills, with a team-oriented mindset and ability to bridge discussions between product and engineering.
• AI Enthusiasm: A genuine interest in leveraging AI technologies to enhance development efficiency and code quality.

Benefits

• Health and dental insurance
• Meal and food allowance
• Extended paternity leave
• Partnership with gyms and health and wellness professionals via Wellhub (Gympass) TotalPass
• Profit Sharing and Results Participation (PLR)
• Life insurance
• Continuous learning platform (CI&T University)
• Discount club
• Free online platform dedicated to physical, mental, and overall well-being
• Pregnancy and responsible parenting course
• Partnerships with online learning platforms
• Language learning platform

And many more!

More details about our benefits here: https://ciandt.com/br/pt-br/carreiras

At CI&T, inclusion starts at the first contact. If you are a person with a disability, it is important to present your assessment during the selection process.See which data needs to be included in the report by clicking here. This way, we can ensure the support and accommodations that you deserve. If you do not yet have the assessment, don't worry: we can support you in obtaining it.

We have a dedicated Health and Well-being team, inclusion specialists, and affinity groups who will be with you at every stage. Count on us to make this journey side by side.